This invention refers to a two-wheeled apparatus for the packaging of filter bags containing an infusion product, fitted with a grasping tag connected to the one end of a handling thread, whose other end is attached to the same bag.
The apparatus comprises two wheels, with multiple pincers, rotating intermittently in opposing directions. The first wheel is rotated in a counterclockwise and the second one in a clockwise direction, while progressively associating with various work stations designed to feed the filter bag, associate the handling thread to the filter bag, attach the thread to the bag, transfer the bag from the first to the second wheel, wrap the thread around the bag, and simultaneously associate the grasping tag to both the thread and the bag. In particular, the invention refers to a filter bag of a so-called bilobate type, where the infusion product is localized in two closed chambers ending at the bottom in a xe2x80x9cWxe2x80x9d shape fold. The invention may also be applied to an eventual one-labe bag of a type which allows it to be produced in a apparatus as described in this invention. The known art envisions various methods for the packaging of filter bags and the attaching of the thread to the bag and the tag, by using apparatus and devices differing from case to case. A known solution is to produce filter bags coated with a heat-sealing layer of thermoplastic material, where the thread is attached to the bag by heat-sealing it between the upper edges. Another solution is a filter bag which is always coated by a thermal sealing material, where the thread is attached at one end to the bag by a thermoplastic stamp, and at the other end to the tag by an additional thermoplastic stamp. These two solutions evidence two serious drawbacks: the first refers to a migration of the infusion of substances originating from the thermoplastic layer, and the second to the high cost of the thermally sealed paper with respect to that of a normal-filter paper. Another known solution is the packaging of the filter bag by using metallic staples to fasten the thread to the bag and tag, a solution which is inconvenient due to the alteration of the infusion""s organic taste characteristics induced by the metal.
Another known solution is to anchor the free end of the thread of the bag by knots, or stitched seams similar to knots or simple linear stitched seams. The available documents make it evident however, that the known art teaches little about the production of industrial] apparatus capable of automating the packaging of filter bags by using these last solutions.
German patent DE 1 229 895 discloses an apparatus, belonging to the prior art, to feed and fix a handling thread to the tag, in a first station, and anchor both thread and tag to the bag in a second station.
The Italian patent application no. M199A000976 in the name of the same Applicant describes a mechanical device for executing multiple Knots, in a sequential manner, of differentiated size and at variable speed, and therefore capable of producing filter bags on an industrial scale and with a broad versatility and flexibility, complete with handling threads and tag, without incurring in any of the drawbacks of the known solutions mentioned above, and without requiring metallic staples as fastening means.
The purpose of the present invention is to disclose an apparatus comprising two wheels, carrying specific devices, apt to anchor, by a series of multiple knots, an handling thread to the top flap of a filter bag, simultaneously closing it, (in the first wheel) and to fix a tag to the other free end of the thread by welding (in the second wheel).
This purpose is achieved by the characteristics derived from the claims outlined below, which will become more evident from the detailed description given in the text and in the attached drawings, which also point to another great advantage of the invention: the simplicity of production and the rational kynematic layout of the diagram, deriving from the elimination of the two systems feeding metallic staples between the bag and thread and the tag and thread), which translates in practice to lower production costs for the entire apparatus, to its improved reliability and to some greater operating energy savings for the final user.